Upshift Indicator Description; Operation; Turn Signal Indicator - Jeep Wrangler 2001 Service Manual

TJ
TURN SIGNAL INDICATORS (Continued)
to diagnose or repair the turn signal indicators.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR - DIAGNOSIS AND TESTING - TURN
SIGNAL & HAZARD WARNING SYSTEM). If no
turn signal and hazard warning system problem is
found, the following procedure will help locate an
open in the right or left turn signal circuits. Refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Remove the instrument cluster from the
instrument panel. Disconnect the instrument panel
wire harness connector (Connector C1) for the instru-
ment cluster from the connector receptacle on the
back of the cluster housing.
(2) Reconnect the battery negative cable. Activate
the hazard warning system by moving the hazard
warning switch button on the left multi-function
switch to the On position. Check for battery voltage
at the inoperative (right or left) turn signal circuit
cavity of the instrument panel wire harness connec-
tor (Connector C1) for the instrument cluster. There
should be a switching (on and off) battery voltage sig-
nal present. If OK, replace the faulty instrument
cluster. If not OK, repair the open (right or left) turn
signal circuit between the instrument cluster and the
left multi-function switch as required.
UPSHIFT INDICATOR
DESCRIPTION
An upshift indicator is standard equipment on all
instrument clusters, however, on vehicles not built
for the United States or Canadian markets and those
not equipped with a manual transmission, this indi-
cator is electronically disabled. The upshift indicator
2001 JEEP WRANGLER
is located near the right upper edge of the instru-
ment cluster overlay, just above the oil pressure
gauge. The upshift indicator consists of an upward
pointed arrow icon that is a stencil-like cutout in the
opaque layer of the instrument cluster overlay. The
dark outer layer of the cluster overlay prevents the
icon from being clearly visible when the lamp is not
illuminated. An amber lens behind the cutout in the
opaque layer of the cluster overlay causes the icon to
appear in amber through the translucent outer layer
of the overlay when it is illuminated from behind by
a Light Emitting Diode (LED) soldered onto the
instrument cluster electronic circuit board. When the
exterior lighting is turned On, the illumination inten-
sity of the part time indicator is one-step dimmable,
which is adjusted using the panel lamps dimmer con-
trol ring on the left multi-function switch control
stalk. The upshift indicator is serviced as a unit with
the instrument cluster.

OPERATION

The upshift indicator gives an indication to the
vehicle operator when the manual transmission
should be shifted to the next highest gear in order to
achieve the best fuel economy. This indicator is con-
trolled by a transistor on the instrument cluster elec-
tronic circuit board based upon cluster programming
and electronic messages received by the cluster from
the Powertrain Control Module (PCM) over the Pro-
grammable Communications Interface (PCI) data
bus. The upshift indicator function of the instrument
cluster is electronically enabled or disabled by a PCI
data bus message received by the cluster from the
PCM. The upshift indicator Light Emitting Diode
(LED) receives battery current on the instrument
cluster electronic circuit board through the fused
ignition switch output (run-start) circuit whenever
the ignition switch is in the On or Start positions;
therefore, the indicator will always be off when the
ignition switch is in any position except On or Start.
The LED only illuminates when it is provided a path
to ground by the instrument cluster transistor. The
instrument cluster will turn on the upshift indicator
for the following reasons:
• Upshift Lamp-On Message - Each time the
cluster receives an upshift lamp-on message from the
PCM indicating the engine speed and load conditions
are right for a transmission upshift to occur, the
upshift
remains illuminated until the cluster receives an
upshift lamp-off message from the PCM or until the
ignition switch is turned to the Off position, which-
ever occurs first. The PCM will normally send an
upshift lamp-off message three to five seconds after a
lamp-on message, if an upshift is not performed. The
indicator will then remain off until the vehicle stops
INSTRUMENT CLUSTER
indicator is illuminated.
8Js - 35
The indicator